What is an external penetration test?
An external penetration test is a security assessment of everything your organization exposes to the public internet, carried out from the position of a remote, unauthenticated attacker. It answers a simple question: if someone targeted your perimeter today, what could they reach, and what could they do once they got in?
Your perimeter is the most exposed part of your infrastructure. It sits in the open, it is scanned constantly, and it is where most breaches begin. An external pentest maps that attack surface, finds the weak points, and shows you which ones a real adversary could exploit — before one does.
What we test (assets in scope)
BackDoor assesses the full range of internet-facing assets, including: public IP ranges (IPv4 and IPv6) and the services behind them; web servers, web applications, and public APIs; mail servers and DNS infrastructure; VPN endpoints and remote-access gateways; cloud-exposed services and misconfigured storage; login portals, admin panels, and forgotten subdomains.
The attacker's perspective (black-box)
We start with no credentials and no inside knowledge — the same blank slate a real attacker has. This black-box approach mirrors how an external threat unfolds: reconnaissance first, then discovery, then exploitation. You see your perimeter the way an adversary sees it, not the way your network diagram says it should look.
Why run an external pentest?
A vulnerability scan tells you what might be wrong. An external pentest proves what a real attacker could do about it. Here is what that buys you:
- Find perimeter gaps before attackers do. Exposed services, outdated software, and misconfigurations get found and fixed on your schedule, not during an incident.
- Prove real exploitability, not theory. We validate every finding with a working proof of concept, so you spend remediation time on the issues that matter — not on scanner noise.
- Meet compliance requirements. External penetration testing supports PCI DSS, SOC 2, ISO 27001, and cyber-insurance requirements for regular, independent testing.
- Reduce breach and downtime risk. Closing perimeter weaknesses cuts the most common path attackers use to reach your data and your customers.
- Give leadership a clear picture. A prioritized report turns technical risk into decisions your team can act on and your board can understand.
Who needs external penetration testing?
If your business runs anything on the public internet, you have a perimeter worth testing. External penetration testing services matter most for:
- SaaS and technology companies whose product, APIs, and customer data live online.
- Fintech, banking, and payments teams under PCI DSS and constant, targeted attack.
- E-commerce operators, where downtime and data loss hit revenue directly.
- Healthcare and any organization handling sensitive records, where a breach carries regulatory weight.
- Any company facing a compliance audit or cyber-insurance renewal that requires independent testing of internet-facing systems.
If you have added infrastructure, launched a product, or gone through a merger since your last test, your attack surface has changed — and so has your risk.
How BackDoor runs your external pentest
BackDoor combines a swarm of AI agents with a proven offensive methodology. The agents work in parallel — 127+ of them, running 300+ attack scenarios — so a full external test that traditionally takes weeks is completed in about five hours, without cutting corners on depth.
Scoping and authorization
You define the targets and rules of engagement. We confirm scope and authorization before any traffic is sent.
Reconnaissance and OSINT
The agents map your real attack surface — domains, subdomains, exposed services, and leaked information — the same footprinting a skilled attacker would perform.
AI-driven scanning and exploitation
127+ agents test 300+ attack scenarios in parallel across your perimeter, chaining findings the way a human operator would, but at machine speed.
PoC validation and CVSS-ranked reporting
We reproduce every confirmed vulnerability with a working proof of concept and rank it by CVSS. You get the full, prioritized report in about five hours — and we retain none of your data afterward.
The result reads like the work of a determined attacker — only this time the outcome is a report you can act on, not a breach you have to disclose.
Vulnerabilities we find on your perimeter
External tests surface a recurring set of weaknesses. On a typical perimeter, BackDoor uncovers:
- Open ports and unnecessary services exposed to the internet — every one is an extra door.
- Outdated software and firmware with known, exploitable CVEs that scans list but never prove.
- Weak network protocols and insecure configurations that leak data or allow interception.
- DNS spoofing and hijacking opportunities that can redirect your users or your mail.
- Denial-of-service exposure on public-facing services that could take you offline.
- Web application and API flaws — injection, broken authentication, and access-control gaps.
- Leaked or default credentials reused across exposed systems, often the fastest way in.
Each one is confirmed with a proof of concept, so you know it is real, you know how bad it is, and you know exactly what to fix first.
What you get: deliverables and sample report
You do not get a raw scanner dump. You get a report your team can act on the same day:
- CVSS-ranked findings, ordered by real-world risk.
- A working proof of concept for every confirmed vulnerability.
- Clear remediation guidance for each issue, written for the people who will fix it.
- A retest to confirm the fixes held.
- Zero data retention — we delete your data after the engagement, by design.
External vs internal vs web application pentest
| Test | Starting point | What it answers |
|---|---|---|
| External | Public internet, no access | What can a remote attacker reach and exploit on my perimeter? |
| Internal | Inside the network | What could an attacker (or insider) do once they are already in? |
| Web application | A specific app | What flaws exist in this application's logic and code? |
Most organizations start with an external pentest, because the perimeter is what attackers hit first. Internal and web application testing extend the picture from there.
Learn more: how network penetration testing works from the outside in.
Where the perimeter ends and the login begins
An external penetration test is unauthenticated by definition. We start with no credentials and no inside knowledge, the same blank slate a real attacker has — and that is the point. This engagement answers what a stranger can reach, not what a customer can.
- Inside this engagementexternal
Everything up to the door
Login portals, VPN gateways, admin panels and SSO endpoints are very much in scope — we just test them from the outside.
- Exposed authentication
- Sign-in rate limiting
- Reset flow enumeration
- Default credentials
- A separate engagementweb app
Everything behind it
What sits behind the door, an external test does not open. That is a deliberate boundary, not a limitation — and it is where most perimeter breaches actually begin.
- Roles and tenants
- Checkout flows
- Customer records
- Admin functionality
If you also need the functionality behind the login covered, that is a web application test, and it runs with test accounts you provide.
Start your external pentestWhy BackDoor
External testing is a high-trust decision — you are letting a partner attack your infrastructure and handle sensitive findings. Here is why teams choose BackDoor:
Proven results
- 100+ companies tested across their external perimeters.
- Every finding PoC-verified — no theoretical noise.
- Zero data retention — nothing about your environment is kept after the engagement.
Our security team and expertise
BackDoor pairs its AI platform with experienced offensive-security engineers who scope, validate, and review every engagement. The AI does the work at scale; people make sure it is right.
Certifications and standards
Our methodology follows PTES, NIST SP 800-115, the OWASP Testing Guide, and OSSTMM.
Pricing
Transparent, fixed-scope pricing — no drawn-out sales cycle before you know the cost. Not sure what your scope needs? Request a quote and we will size it with you.